Investigations on the radiation characteristics of new hollow dielectric horn antennas

Investigations on the design and development of certain new hollow dielectric hom antennas of rectangular cross section have been carried out. The main shortcoming of the existing ordinary hollow dielectric hom antenna (HDH) is the abrupt discontinuity at the feed-end. A new launching technique using a dielectric rod is introduced to overcome this limitation. Also a strip loading technique is employed for further modification of the antenna. Radiation parameters of new I-IDH antennas of Eplane sectoral, H-plane sectoral and pyramidal types were studied and are found to be very attractive. Theoretical approach based on Marcatili���s principle and two aperture theory along with diffraction theory and image theory is used to support the experimental findings. The HDH is considered as solid horn of effective dielectric constant and the aperture field is evaluated. The antenna is excited by the open waveguide in the dominant TE1o mode and so the existence of any hybrid mode is mled-out. The theoretical results are observed to be in good agreement with the experimental results.

Studies on High- Tc Superconductors with Inequivalent Conducting Layers

The thesis deals with the study of super conducting properties of layered cuprates within the frame work of a modified Lawrence-Doniach (LD) model. The thesis is organized in seven chapters. Chapter I is a survey of the phenomena and theories of conventional superconductivity which can serve as a springboard for launching the study of the new class of oxide superconductors and it also includes a chronological description of the efforts made to overcome the temperature barrier. Chapter II deals with the structure and properties of the copper oxide superconductors and also the experimental constraints on the theories of high te:::nperature superconductivity. A modified Lawrence-Doniach type of phenomenological model which forms the basis of the presnt study is also discussed. In chapter III~ the temperature dependence of the upper critical field both parallel and perpendicular to the layers is determined and the results are compared with d.c. magnetization measurements on different superconducting compoilllds. The temperature and angular dependence of the lower critical field both parallel and perpendicular to the layers is also discussed. Chapters IV, V and VI deal with thermal fluctuation effects on superconducting properties. Fluctuation specific heat is studied in chapter IV. Paraconductivity both parallel and perpendicular to the layers is discussed in chapter V. Fluctuation diamagnetism is dealt with in chapter VI. Dimensional cross over in the fluctuation regime of all these quantities is also discussed. Chapter VII gives a summary of the results and the conclusions arrived at.

Dipodal Ferrocene Derivatives for Nanostructured Redox-Functionalised Surfaces

Self-assembled monolayers (SAMs) on solid surfaces are of great current interest in science and nanotechnology. This thesis describes the preparation of several symmetrically 1,1���-substituted ferrocene derivatives that contain anchoring groups suitable for chemisorption on gold and may give rise to SAMs with electrochemically switchable properties. The binding groups are isocyano (-NC), isothiocyanato (-NCS), phosphanyl (-PPh2), thioether (-SR) and thienyl. In the context of SAM fabrication, isothiocyanates and phosphanes are adsorbate systems which, surprisingly, have remained essentially unexplored. SAMs on gold have been fabricated with the adsorbates from solution and investigated primarily by X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure spectroscopy. The results of these analytical investigations are presented and discussed in matters of the film quality and possible binding modes. The quality of self-assembled monolayers fabricated from 1,1���-diisocyanoferrocene and 1,1���-diisothiocyanatoferrocene turned out to be superior to that of films based on the other adsorbate species investigated. Films of those absorbates as well as of dppf afforded well-defined SAMs of good quality. All other films of this study based on sulfur containing anchoring groups exhibit chemical inhomogeneity and low orientational order of the film constituents and therefore failed to give rise to well-defined SAMs. Surface coordination chemistry is naturally related to molecular coordination chemistry. Since all SAMs described in this thesis were prepared on gold (111) surfaces, the ferrocene-based ligands of this study have been investigated in their ability for complexation towards gold(I). The sulfur-based ferrocene ligands [fc(SR)2] failed to give stable gold(I) complexes. In contrast, 1,1���-diisocyanoferrocene (1) proved to be an excellent ligand for the complexation of gold(I). Several complexes were prepared and characterised utilising a series of gold(I) acetylides. These complexes show interesting structural motifs in the solid state, since intramolecular aurophilic interactions lead to a parallel orientation of the isocyano moieties, combined with an antiparallel alignment of neighbouring units. The reaction of 1 with the gold(I) acetylide [Au(C���C���Fc)]n turned out to be very unusual, since the two chemically equivalent isocyano groups undergo a different reaction. One group shows an ordinary coordination and the other one undergoes an extraordinary 1,1-insertion into the Au-C bond. As a sideline of the research of this thesis several ferrocene derivatives have been tested for their suitability for potential surface reactions. Copper(I) mediated 1,3-dipolar cycloadditions of azidoferrocene derivatives with terminal alkynes appeared very promising in this context, but failed to a certain extent in terms of ���click��� chemistry, since the formation of the triazoles depended on the strict exclusion of oxygen and moisture and yields were only moderate. Staudinger reactions between dppf and azidoferrocene derivatives were also tested. The nucleophilic additions of secondary amines to 1,1���-diisothiocyanatoferrocene led to the respective thiourea derivatives in quantitative yields.

Ferrocene-Based Pyridylphosphine Ligands ��� Coordination Chemistry of Group 10, 11 and 12 Metals

English: The present thesis describes the synthesis of 1,1���-ferrocendiyl-based pyridylphosphine ligands, the exploration of their fundamental coordination chemistry and preliminary experiments with selected complexes aimed at potential applications. One main aspect is the synthesis of the bidentate ferrocene-based pyridylphosphine ligands 1-(Pyrid-2-yl)-1���-diphenylphosphinoferrocene, 1-(Pyrid-3-yl)-1���-diphenylphosphinoferrocene and 1-[(Pyrid-2-yl)methyl]-1���-diphenylphosphinoferrocene. A specific feature of these ligands is the ball-bearing like flexibility of the ferrocenebased backbone. An additional flexibility element is the rotation around the C���C single bonds. Consequently, the donor atoms can realise a wide range of positions with respect to each other and are therefore able to adapt to the coordination requirements of different metal centres. The flexibility of the ligand also plays a role in another key aspect of this work, which concerns the coordination mode, i. e. bridging vs. chelating. In addition to the flexibility, also the position of the donor atoms to each other is important. This is largely affected by the position of the pyridyl nitrogen (pyrid-2-yl vs. pyrid-3-yl) and the methylen group in 1-[(Pyrid-2-yl)methyl]-1���-diphenylphosphinoferrocene. Another interesting point is the combination of a soft phosphorus donor atom with a harder nitrogen donor atom, according to the HSAB principle. This combination generates a unique binding profile, since the pi-acceptor character of the P site is able to stabilise a metal centre in a low oxidation state, while the nitrogen sigma-donor ability can make the metal more susceptible to oxidative addition reactions. A P,N-donor combination can afford hemilabile binding profiles, which would be ideal for catalysis. Beyond 1,2-substituted ferrocene derivatives, which are quite successful in catalytic applications, 1,1���-derivatives are rather underrepresented. While a low-yield synthetic pathway to 1-(Pyrid-2-yl)-1���-diphenylphosphinoferrocene was already described in the literature [I. R. Butler, Organometallics 1992, 11, 74.], it was possible to find a new, improved and simplified synthetic pathway. Both other ligands were unknown prior to this work. Satisfactory results in the synthesis of 1-(Pyrid-3-yl)-1���-diphenylphosphinoferrocene could be achieved by working in analogy to the new synthetic procedure for 1-(Pyrid-2-yl)-1���-diphenylphosphinoferrocene. The synthesis of 1-[(Pyrid-2-yl)methyl]-1���-diphenylphosphinoferrocene has been handled by the group of Prof. Petr Stepnicka from Charles University, Prague, Czech Republic. The synthesis of tridentate ligands with an analogous heterodentate arrangement, was investigated briefly as a sideline of this study. The major part of this thesis deals with the fundamental coordination chemistry towards transition metals of the groups 10, 11 and 12. Due to the well-established catalytic properties of analogous palladium complexes, the coordination chemistry towards palladium (group 10) is of particular interest. The metals zinc and cadmium (group 12) are also of substantial importance because they are redox-inert in their divalent state. This is relevant in view of electrochemical investigations concerning the utilisation of the ligands as molecular redox sensors. Also mercury and the monovalent metals silver and gold (group 11) are included because of their rich coordination chemistry. It is essential to answer questions concerning aspects of the ligands��� coordination mode bearing in mind the HSAB principle.

Plan de negocios Muy Mirona

Evidenciamos las necesidades de la mujer bogotana, m��s exactamente la falta de dise��o y exclusividad en el calzado de las mujeres. Por ello en julio de 2010 se crea la empresa Muy Mirona. Una empresa conformada por dos estudiantes de (21) a��os, siendo una socia estudiante de la Universidad del Rosario y la otra estudiante de la Salle College, quienes tienen el objetivo de posicionar la organizaci��n como una de las mejores empresas en innovaci��n de calzado y as�� fomentar el empleo de personas mayores de 40 a��os para generar un impacto social positivo en la sociedad capitalina. Despu��s de d��as y con miles de ideas surgi�� el nombre de nuestra empresa ���Muy Mirona��� como una forma divertida e interesante de captar a nuestras clientas que tienen como objetivo ser diferentes y ��nicas. Al d��a de hoy hemos tenido el gusto de lanzar tres colecciones la primer Nice Too Meet You, en donde se hizo ��nfasis en la comodidad, los zapatos que dise��amos para esta colecci��n fueron planos, utilizamos materiales sint��ticos que se caracterizaban por la variedad de sus colores. La segunda colecci��n Nice Too Meet You Two, se diferencio de la primera debido a la incursi��n que tuvimos en materiales tales como el cuero, taches, gamuzas, e introdujimos una nueva l��nea de tac��n peque��o es decir tac��n 4/5 que fue todo un ��xito. Finalmente en la tercera colecci��n Madonna Bastarda decidimos ir mas all��, entrando en el tac��n high es decir tac��n de 12 cent��metros con plataformas livianas para el manejo funcional de nuestras clientas, en esta colecci��n variamos el portafolio no solo de los modelos sino tambi��n de los materiales y de los dise��os, sin abandonar nuestra adorada l��nea de zapatos planos ya que tambi��n sacamos referencias de este tipo de zapato en la ��ltima colecci��n. A lo largo de nuestra vida activa como empresa, hemos tenido la oportunidad de participar activamente en eventos como la feria de la universidad del rosario y la semana internacional de la moda de Bogot��, la feria de j��venes empresarios ,en donde hemos contado con la acogida de gran cantidad de p��blico, consolid��ndonos como una de las pocas empresas de dise��o exclusivo de calzado para dama, ratificando nuestro compromiso con un trabajo de calidad y con una visi��n hacia el futuro. A lo largo de este tiempo hemos vivido experiencias invaluables que nos hacen ser lo que somos hoy en d��a, buscamos estar preparadas para los retos venideros reinvent��ndonos en cada una de nuestras colecciones. Permitiendo que Muy Mirona sea reconocida a nivel nacional e internacional como una empresa que entiende los deseos y las necesidades de las mujeres y que logra convertir esto en comodidad y funcionalidad, deseamos dirigirnos a todas las mujeres modernas, amantes de la moda, dispuestas a portar unos hermosos zapatos de fina coqueter��a cargados de estilo, sin llegar a lo soso y a lo extravagante.

Company Challenge Project: L'Or��al Brandstorm 2013

Creaci��n de plan de negocios completo, para la escogencia y el lanzamiento de un producto de la l��nea L���Or��al Paris que no estuviera presente en el mercado del sudeste asi��tico (Singapur, Filipinas, Camboya, Laos, Indonesia, Malasia) e India, y adicionalmente crear un nuevo producto que estuviera ligado al escogido en la primera parte.

Formulaci��n Modelo de Negocio Getr��nk

La idea de negocio consiste en ofrecer al mercado una bebida refrescantemente novedosa. La bebida consiste en un concentrado de fruta hecho a base de pulpa natural el cual rinde seis veces su contenido, siendo ideal para la familia en general y establecimientos en los que se sirvan bebidas. Se estima que hay alrededor de 200 mil familias que podri��an ajustarse al perfil de consumidores potenciales en Bogota��. Para comprobar el potencial del producto se hizo una validacio��n de este en la Ciclovia especi��ficamente en un punto donde practicari��an deporte familias con caracteri��sticas a las preestablecidas en la descripcio��n de clientes potenciales, favorablemente las apreciaciones hacia el producto fueron positivas hasta el punto en que se genero expectativa por el lanzamiento del producto al mercado, adema��s se validaron hipo��tesis planteadas durante la formulacio��n del modelo de negocio. El enfoque inicial de la empresa seria desarrollar el mercado, comercializar la bebida atreves de sus canales, realizar constantes investigaciones de mercado con el fin de entender las necesidades de sus clientes y de esta forma fidelizarlos.

Internacionalizaci��n de la mora Colombiana a Alemania Frusan (San Bernardo Cundinamarca) una asociaci��n con gran potencial de exportaci��n al mercado aleman

Sin lugar a duda este trabajo cumple con las principales expectativas de un posible emprendedor en la Comercializaci��n de productos al exterior, aqu�� podemos encontrar las principales bases y sobre todo una estructura para lograr entender el sistema que conforma de un Plan de Exportaci��n, el cual puede ser tomado y f��cilmente adaptado a cualquier producto que deseemos Comercializar. Una vez logrado el objetivo de emprender un camino hacia la Comercializaci��n al Exterior, es importante no detenerse con los logros alcanzados, el camino a penas comienza y sin lugar a dudad lo mas importante es lograr perdurar en el tiempo y mantener un equilibrio en el que todos ganemos (Mentalidad de negociaci��n Gana ��� Gana).

Estudio de caso- lanzamiento de la marca Davivienda en Costa Rica, el Salvador y Honduras

Este documento tiene como prop��sito reunir y analizar el universo de informaci��n disponible al respecto del proceso de Lanzamiento de la Marca Davivienda en tres mercados Centroamericanos: Costa Rica, El Salvador y Honduras y as��, lograr aprovechar al m��ximo las experiencias y lecciones aprendidas por la entidad durante este per��odo. Para este prop��sito, la estructura del trabajo consta de un marco te��rico que contempla las teor��as sobre el posicionamiento de marca, procediendo a un estudio de caso formal. Este estudio se compone inicialmente de la descripci��n del Banco Davivienda y los pa��ses en los que la entidad ingres�� tras la adquisici��n de la operaci��n de HSBC. Posteriormente, se analiza el proceso del Lanzamiento de Marca desde la formulaci��n e implementaci��n de la estrategia hasta la evaluaci��n y an��lisis de los resultados obtenidos. Por ��ltimo, se presentan las conclusiones y recomendaciones con base en la teor��a, resultados y aprendizajes.

La construcci��n de un sistema de migraci��n entre M��xico y Estado Unidos. Una aproximaci��n a los chicanos (d��cada de los 60 al 2000)

El inter��s de esta monograf��a es la construcci��n de un Sistema de Migraci��n entre M��xico y Estados Unidos, a trav��s de la creaci��n del grupo identitario Chicano. Se va analizar desde la teor��a de Sistemas de Migraci��n de Oliver Bakewell, las razones por las cuales los Chicanos en la d��cada de los 60 hasta el 2000 en el sudeste de Estados Unidos, pueden entenderse como un Sistema de Migraci��n. Los Chicanos pueden ser entendidos como un Sistema de Migraci��n, a partir de la interacci��n de flujos migratorios como personas, bienes y redes de informaci��n; instituciones como tratados, redes de migraci��n ilegal y oportunidades laborales; estrategias, de parte de los Estados o agentes que permiten o restringe la migraci��n, por medio de leyes y pol��ticas migratorias, lo anterior tiene una reacci��n diferente en los siguientes puntos: origen, tr��nsito y destino de los migrantes mexicanos.

Model for calculating the sustainable building index (SBI) in the kingdom of Bahrain

We have developed a model that allows players in the building and construction sector and the energy policy makers on energy strategies to be able to perceive the interest of investors in the kingdom of Bahrain in conducting Building Integrated Photovoltaic (BIPV) or Building integrated wind turbines (BIWT) projects, i.e. a partial sustainable or green buildings. The model allows the calculation of the Sustainable building index (SBI), which ranges from 0.1 (lowest) to 1.0 (highest); the higher figure the more chance for launching BIPV or BIWT. This model was tested in Bahrain and the calculated SBI was found 0.47. This means that an extensive effort must be made through policies on renewable energy, renewable energy education, and incentives to BIPV and BIWT projects, environmental awareness and promotion to clean and sustainable energy for building and construction projects. Our model can be used internationally to create a "Global SBI" database. The Sustainable building and construction initiative (SBCI), United Nation, can take the task for establishing such task using this model.

Directed search with real options

While search is normally modelled by economists purely in terms of decisions over making observations, this paper models it as a process in which information is gained through feedback from innovatory product launches. The information gained can then be used to decide whether to exercise real options. In the model the initial decisions involve a product design and the scale of production capacity. There are then real options to change these factors based on what is learned. The case of launching product variants in parallel is also considered. Under ���true��� uncertainty, the model can be seen in terms of heuristic decision-making based on subjective beliefs with limited foresight. Search costs, the values of the real options, beliefs, and the cost of capital are all shown to be significant in determining the search path.

Generation of inertia-gravity waves in the rotating thermal annulus by a localised boundary layer instability

Waves with periods shorter than the inertial period exist in the atmosphere (as inertia-gravity waves) and in the oceans (as Poincar�� and internal gravity waves). Such waves owe their origin to various mechanisms, but of particular interest are those arising either from local secondary instabilities or spontaneous emission due to loss of balance. These phenomena have been studied in the laboratory, both in the mechanically-forced and the thermally-forced rotating annulus. Their generation mechanisms, especially in the latter system, have not yet been fully understood, however. Here we examine short period waves in a numerical model of the rotating thermal annulus, and show how the results are consistent with those from earlier laboratory experiments. We then show how these waves are consistent with being inertia-gravity waves generated by a localised instability within the thermal boundary layer, the location of which is determined by regions of strong shear and downwelling at certain points within a large-scale baroclinic wave flow. The resulting instability launches small-scale inertia-gravity waves into the geostrophic interior of the flow. Their behaviour is captured in fully nonlinear numerical simulations in a finite-difference, 3D Boussinesq Navier-Stokes model. Such a mechanism has many similarities with those responsible for launching small- and meso-scale inertia-gravity waves in the atmosphere from fronts and local convection.

Climatology and predictability of the late summer stratospheric zonal wind turnaround over Vanscoy, Saskatchewan

A climatology of the late summer stratospheric zonal wind turnaround phenomenon is presented, with a particular focus on the behaviour over the Meteorological Service of Canada���s balloon-launching site at Vanscoy, Saskatchewan (52��N, 107��W). Turnaround refers to the change in sign of the zonal wind velocity and occurs twice each year at stratospheric mid-latitudes, in early spring and in late summer. The late summer turnaround is of particular interest to the high-altitude ballooning community because it offers the ideal conditions for launch, but it is also an interesting dynamical phenomenon in its own right. It is studied here using both the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis and the United Kingdom Meteorological Office (MetO) analysis products as well as climate simulation data from the Canadian Middle Atmosphere Model (CMAM). The phenomenon and its interannual variability are documented. The predictability of the late summer turnaround over Vanscoy is investigated using both statistical averages and autocorrelation analysis. From the statistical averages, it is found that during every year since 1993, the period from 26 August to 5 September has contained appropriate launch dates. From the autocorrelation analysis, it is found that stratospheric zonal wind anomalies can persist for a month or more during most of the summer, but there is a predictability horizon at the end of the summer ��� just before turnaround

Voluntary action and causality in temporal binding

Previous studies have documented temporal attraction in perceived times of actions and their effects. While some authors argue that voluntary action is a necessary condition for this phenomenon, others claim that the causal relationship between action and effect is the crucial ingredient. In the present study, we investigate voluntary action and causality as the necessary and sufficient conditions for temporal binding. We used a variation of the launching effect proposed by Michotte, in which participants controlled the launch stimulus in some blocks. Volunteers reported causality ratings and estimated the interval between the two events. Our results show dissociations between causality ratings and temporal estimation. While causality ratings are not affected by voluntary action, temporal bindings were only found in the presence of both voluntary action and high causality. Our results indicate that voluntary action and causality are both necessary for the emergence of temporal binding.